Current code for uploading data to blob service is tightly coupled to the ksyerver uploads table and expo-file-system library which I don't think it the case for e2e notifs so this code would require some refactoring to support e2e notifs case. We could move the current code that is on the keyserver to lib but this code uses fetch library. However @bartek told me that it might not work well on native. Therefore given the fact that we haven't even started notif session intialization between clients (which is far more important) I am willing to cut a scope here. Returning error message from this funciton won't crash notif generation and delivery. It will just be delivered without message infos if it exceeds push service limit.